There has been known a conventional static random access memory (SRAM) using a field effect tunnel transistor that takes advantage of semiconductor band-to-band tunneling. Use of such a field effect tunnel transistor makes it possible to reduce a power supply voltage and reduce power consumption as compared with the use of a conventional metal insulator semiconductor field effect transistor (MISFET). However, the field effect tunnel transistor has a problem of a complex pattern of an impurity implantation region in an SRAM cell because a source region and a drain region are different in conductivity type. This causes difficulty in lithography for forming a mask for use in ion implantation, and may therefore prevent precise implantation of an impurity and vary transistor characteristics.